The ruling, which received little public attention when it was issued July 29, struck down a rule that allowed appellate judges to set aside convictions on sex crimes if they thought the victim's testimony wasn't credible. The state Supreme Court said the corroboration rule required appellate judges to make determinations they were not equipped to make.

Judge Richard Teitelman wrote in the unanimous opinion that in every other crime, appellate judges assume evidence supporting a conviction is true, and generally consider only if there is enough evidence.

The corroboration rule combined a discredited premise that victims of sex assaults lie more often than other victims with the idea "that judges and juries are uniquely unable to make accurate factual determinations in sex crime cases. Both assumptions are unsupported," Teitelman wrote.

The court also struck down a "destructive contradictions" rule that allowed appellate courts to throw out convictions if a witness contradicts statements made during their court

testimony or in earlier proceedings.

The ruling came in the case of Sylvester Porter of St. Louis, who challenged his conviction and 25-year sentence on two first-degree statutory sodomy counts involving a 3-year-old girl. The girl was 5 when she testified at Porter's trial and his attorneys argued in an appeal that her testimony was not corroborated and was contradictory.

Porter's attorneys invoked the destructive contradictions rule because the victim gave different details at different times, which often happens with child victims, said Jerri Sites, child advocacy center program director at Rainbow House.

Child abuse victims "may make a clear disclosure in a forensic interview, and get to court, and they freeze when they are facing their abuser," Sites said.

The practical effect of the decision is likely to be small but the decision has major significance in the development of the law, said Ben Trachtenberg, an associate professor of law at the University of Missouri.

"It shows Missouri following a modern trend of getting rid of some antiquated rules that apply only in sex cases and the theory that victim witnesses in sex cases, primarily women, were necessarily more unreliable than in other cases," Trachtenberg said.